AT4 style pneumatic

[iknowmy3tables]

I wanted to make a compact toolies valve spudgun for a while, but now that I've landed a summer job at a lab with a machine shop I decided to build this thing while I still had access to professional resources. I intend to use this to make it rain Nerf darts in Humans vs Zombies games.



according to GGDT the muzzle velocity of a cluster of 30 Nerf darts with wadding should be around 100fps which is a decent speed for nerf darts, and I've tested this with a bundled sock which gets ranges of ~100feet at a semi flat angle to the ground.



for comparison this an early prototype of an AT4


originally I planned on piloting this with a hose and a blowgun on the side but that was too optimistic even with an oring seal on my piston


instead I opted to directly mount a 1/4" ball valve triggered opened via a string which works great


I'm pretty happy with it, it has as much power as I need and I can finaly bring a cannon with me to college and shoot it too

[Lockednloaded]

Very cool! I like how clean and simple the inline design is. What is the porting on this thing?

[iknowmy3tables]

The porting is a 1" hole, i made an oring sealed plug out of aluminum and i drilled out the hole on the lathe but if the shop had a bigger drill i would have made a bigger port

[iknowmy3tables]

mind if I bump this with a video?
[youtube][/youtube]

[sharpshooter11000]

Is the ball valve and string a good pilot? I've been making a co axial AT4 style launcher and was thinking of piloting it with a QEV and blowgun pilot but I didn't want to have a bulky air line running down the side. Or I might just use an electronically actuated valve...

Nice clean cannon by the way! Any plans on painting it or anything?

[iknowmy3tables]

The ball valve is a very good pilot for my setup, the string actually helps you consistently open it quickly, however you will have to modify the handle so it points in the right direction. you should also have an oring seal on the piston It'll still work with a duct tape seal but not nearly as well

Imo a QEV is a waste, according to ggdt my piston valve ggdt doesn't show any significant increases in performance with larger vents so really it's depend on how quickly air in your chamber will escape into your pilot

I don't have any plans for paint jobs since I use this in HvZ I can't paint this too look like a gunlike, however I do plan to put the words "SHOCK AND AWE" on the side in bold stencils inspired by the expendables 2